CN109590009A - SiC/C3N4/BiVO4The preparation method of composite photo-catalyst - Google Patents

Abstract

The invention belongs to the technical field of waste water processing using solar energy, and in particular to a kind of SiC/C₃N₄/BiVO₄The preparation method of composite photo-catalyst, comprising the following steps: silicon carbide ultrasonic disperse in the aqueous solution of melamine, 10-60min is stirred at 60-100 DEG C, is then cooled down by A., and decompression filters, and obtains solid mixture A；B. it will be ground after solid mixture A drying, be heated to 400-600 DEG C from room temperature under 5-20 DEG C/min, 2-5h is then kept the temperature at 400-600 DEG C, cooling, grinding obtains SiC-C₃N₄；C. by SiC-C₃N₄It is added in ammonium metavanadate solution, then bismuth nitrate solution is added in ultrasonic disperse again, adjust the pH to 2-14 of solution, be stirred to react in a water bath, and decompression filters, and obtained mixture B is washed to neutrality, then by mixture B drying, grinding.SiC/C made from method of the invention₃N₄/BiVO₄The light degradation ability of composite photo-catalyst is significantly improved.

Description

SiC/C3N4/BiVO4The preparation method of composite photo-catalyst

Technical field

The invention belongs to the technical field of waste water processing using solar energy, and in particular to a kind of SiC/C₃N₄/BiVO₄It is compound The preparation method of photochemical catalyst.

Background technique

The abundant and effective supply of the energy is to ensure the national economic development, and (" coal is more for the fundamental safeguarded national security Co-production technology and Hydrogen Technology ", Xiao Yunhan etc., North China Electric Power University's journal are the 6th phase of volume 31 in 2004, the 5-9 pages, open On November 30th, 2004 day).It is that the whole world disappears using coal, oil and natural gas as the fossil energy of representative over the past decades The main energy of consumption.However, long-term exhaustive exploitation causes fossil energy increasingly withered with the development of economy and human society It exhausts, in addition the production of the energy, conversion and use bring serious environmental pollution, ecosystem destruction and climate change etc. are asked Topic constitutes serious threat (" new energy strategy and national economy sustainable development ", Lee to the survival and development of mankind itself Fine jade, Chinese collective economy, the 5th phase in 2017, the 29-31 pages, publication date on 04 06th, 2017；" coal poly-generation technology and Hydrogen Technology ", Xiao Yunhan etc., North China Electric Power University's journal, the 6th phase of volume 31 in 2004, the 5-9 pages, publication date 2004 years 11 The moon 30).Simultaneously as the sharp increase of the size of population, the random row of modern industry waste water left about, municipal refuse, rural area pesticide Sprinkling etc., causing is already few freshwater resources aggravation shortage, and wherein dyeing is all to cause water all the time (" solving dyeing water pollution problems by technological progress ", Sun Ruizhe etc., environment is protected in pollution problem more serious source Shield, the 19th phase in 2007, the 33-35 pages, publication date on December 31st, 2007；" dyeing water pollution control technical problem with It is recommended that ", Zhang Qiongfang, the economic guide of science and technology, the 27th phase in 2016, page 80, publication date on December 31st, 2016).Moreover, dyestuff Waste water has that complicated component, coloration are high, concentration is big, strong toxicity, hard-degraded substance are more, water quality and quantity fluctuates big and unstable etc. spies Point, current dye species increase in addition, and have the characteristics that anti-light solution, anti-oxidant, antibiooxidation mostly, to increase dye Expect processing difficulty (" the composite photocatalyst Co of waste water²⁺/TiO₂Degradation dye wastewater methylene blue ", Wan Xiang, Jiangsu are big Learn master thesis, 2010, page 1, publication date on October 31st, 2010；" it is useless that Fenton oxidation handles methyl orange dye The research of water ", sudden and violent refined refined, Jiangsu University's master thesis, 2006, page 2, publication date on December 31st, 2006).

Treatment method of printing and dying wastewater can be divided into physical method, chemical method and biochemical method three categories.Wherein, physical method passes through suction Pollutant is separated from the water by the processes such as attached, sedimentation, mechanically decoupled, so that big sand grains and solids Soft flocks are removed, including from The right precipitation method, filtration method, absorption method and centrifugal separation etc..Chemical method utilizes the chemical characteristic of organic pollutant, makes itself and its His compound reaction generates precipitating, gas or is transformed into the method for other innocuous substances to handle waste water, including neutralisation, cohesion Method (flocking settling method and cohesion buoyance lift method) etc..Contaminant degradation is harmless substance by the effect of microorganism by biochemical method, It is removed to decompose useless Organic substance in water, including activated sludge process, biological filter process, anaerobic digestion and oxidation pond process etc.. But above method has the disadvantage that (1) part that hardly degraded organic substance cannot effectively be degraded；(2) physical treatment method It is merely able to shift harmful substance, cannot thoroughly eliminate；It is (3) lower for low-concentration organic waste water treatment efficiency that (" printing and dyeing are useless The progress of method for treating water ", Wang Ping, chemical industry environmental protection, its 5 phase of volume 17 in 1997, the 273-277 pages, publication date 1997 On December 31, in；" research of Degradation of Organo-pollutants in Water with Photo-catalysis ", Chen Jianqiu, Chinese Marine University's master thesis, 2006, the 15-16 pages, publication date on December 31st, 2006).

Photocatalysis technology is the binding site of photochemistry and catalytic chemistry, is a kind of emerging, efficient, energy-efficient modernization sewage Processing technique, have it is easily controllable, secondary pollution will not be generated, low energy consumption, and oxidability is strong, and most organic pollutants can It is carbon dioxide, water and mineral salt by exhaustive oxidation, degree of purification is high, and the advantages such as applied widely receive the extensive of people Concern (" Degradation of Organo-pollutants in Water with Photo-catalysis status and prospectives ", Cui Yumin etc., chemistry of fuel journal, 2004 years the The phase of volume 32 the 1st, the 123-128 pages, publication date on February 29th, 2004；" nanometer H₃P₁₂O₄₀/TiO₂Composite material is to two kinds of dyestuffs Photocatalytic degradation research ", Zhang Hao, Northeast Normal University's master thesis, 2010, page 1, publication date in December, 2010 31 days；" photocatalytic degradation of large biological molecule is studied ", Yang Guiqin, University of Fuzhou's master thesis, 2005, abstract was public Open on December 2005 day 31).

Currently, the research of catalyzing and degrading pollutant has been achieved for biggish progress under ultraviolet light conditions.But it is ultraviolet Light is less than 4% in solar spectrum, and visible light accounts for 43%.Therefore, development efficiently has the corresponding photochemical catalyst of visible light It is an important research topic of current photocatalysis field, there is important research significance (" Ag- base plasma resonance light The progress of catalyst ", Xing Yangyang etc., functional material, the 16th phase of volume 43 in 2012, the 2126-2130 pages, publication date On December 31st, 2012).

Bi series photocatalyst (such as Bi₂O₃、Bi₂WO₄、BiVO₄, BiOBr, BiOCl etc.), because it is with visible light-responded, nothing Evil is nontoxic, and stable, at low cost, advantages of environment protection has been widely studied the (" modification of bismuthino visible light catalytic material And its research of photocatalysis performance ", Liu Houguang, Central China University of Science and Technology's master thesis, 2012, the 6-7 pages, publication date On December 31st, 2012；" pucherite preparation and the research of photocatalysis performance ", Xu Yupeng, Heilongjiang University's master thesis, 2014, abstract, publication date on December 31st, 2014；" the design synthesis of silver-based nanocomposite and its visible light catalytic Can research ", Chen Changfeng, Jiangxi Normal University's master thesis, 2018, page 6, publication date on December 31st, 2018).Its In, pucherite (BiVO₄) there is nontoxic, pollution-free, good weatherability, good corrosion resistance, advantages of environment protection, especially have The advantages that forbidden bandwidth is narrow, high chemical stability, Gao Taiyang light utilization efficiency, and become the research hotspot (" vanadic acid of photocatalysis field The preparation of bismuth yellow ceramic decoration material and its research of color generation property ", Zhang Lian, Shaanxi Tech Univ's master thesis, 2013, abstract, publication date on October 08th, 2013；" controlledly synthesis of pucherite and the research of photocatalysis performance ", cuckoo, Shan Western University of Science and Technology, 2012 page 1, publication date on 09 03rd, 2012；" the modifying agent photocatalysis of composite bismuth vanadium photocatalyst The research of performance ", Zhang Lili, Shaanxi Tech Univ's master thesis, abstract, publication date on December 31st, 2014).

However, the photocatalytic activity of pucherite is lower.Although using different synthetic methods, such as change reaction temperature, instead Between seasonable, precursor liquid pH value, the means such as template are added can improve its photocatalytic activity to a certain extent, however, with big Most photochemical catalysts are the same, and the high recombination rate of photo-generate electron-hole is the main reason for causing the photocatalysis rate of pucherite low, Therefore, the recombination probability for reducing photo-generate electron-hole is to improve active crucial (" the pucherite complex light of bismuth vanadate photocatalyst The research of the modifying agent photocatalysis performance of catalyst ", Zhang Lili, Shaanxi Tech Univ's master thesis, page 4, publication date On December 31st, 2014).

Currently, being modified to photochemical catalyst so that the common method for the recombination probability for reducing photo-generate electron-hole is main Have: (" the modifying agent photocatalysis performance of composite bismuth vanadium photocatalyst is ground for noble metal loading, ion doping, semiconductors coupling etc. Study carefully ", Zhang Lili, Shaanxi Tech Univ's master thesis, page 4, publication date on December 31st, 2014).These methods although Short time its photocatalysis efficiency can be improved, however, being easy to appear and partly leading if depth extends the light-catalyzed reaction time or recycles The problem of body structural instability.Therefore, how to improve that efficiency of light absorption existing for pucherite is low, photo-generated carrier separation energy comprehensively The problems such as power is weaker, photocatalytic activity is poor, catalyst structure stability is still the technical problem of this field urgent need to resolve.

Summary of the invention

In view of this, the purpose of the present invention is to provide a kind of SiC/C₃N₄/BiVO₄The preparation method of composite photo-catalyst.

To achieve the above object, the technical solution of the present invention is as follows:

SiC/C₃N₄/BiVO₄The preparation method of composite photo-catalyst, comprising the following steps:

A. by silicon carbide ultrasonic disperse in the aqueous solution of melamine, 10min is stirred at 60-100 DEG C, it is then cold But, decompression filters, and obtains solid mixture A；

B. will solid mixture A drying after grind, be heated to 400-600 DEG C from room temperature under 5-20 DEG C/min, then in 1-5h is kept the temperature at 400-600 DEG C, cooling, grinding obtains SiC-C₃N₄；

C. by SiC-C₃N₄It is added in ammonium metavanadate solution, ultrasonic disperse, bismuth nitrate solution is then added again, adjust molten The pH to 2-14 of liquid, is stirred to react in a water bath, and decompression filters, and obtained mixture B is washed to neutrality, then by mixture B drying, grinding.

Further, in step A, the mass ratio of the melamine contained in the aqueous solution of silicon carbide and melamine are as follows: 1: 25-1:200。

Further, the parameter setting during the ultrasonic disperse are as follows: power 100-500W, working frequency 20- 60KHz, time 1-30min.

Further, it is specially to filter under -0.1MPa pressure that the decompression, which filters,.

Further, the temperature of the drying is 60-120 DEG C, time 1-6h.

Further, in step C, the mass ratio of the ammonium metavanadate and silicon carbide that contain in ammonium metavanadate solution is 1:500-1: 10。

Further, the temperature of the stirred in water bath reaction is 60-100 DEG C, time 1-6h.

Further, the SiC/C₃N₄/BiVO₄The preparation method of composite photo-catalyst, comprising the following steps:

A. by silicon carbide ultrasonic disperse in the aqueous solution of melamine, 1-300min is stirred at 60-100 DEG C, then Cooling, decompression filters, and obtains solid mixture A, the quality of the melamine contained in the aqueous solution of silicon carbide and melamine Than are as follows: 1:25-1:200；

B. will solid mixture A drying after grind, be heated to 400-600 DEG C from room temperature under 5-20 DEG C/min, then in 1-5h is kept the temperature at 400-600 DEG C, cooling, grinding obtains SiC-C₃N₄；

C. by SiC-C₃N₄It is added in ammonium metavanadate solution, ultrasonic disperse, bismuth nitrate solution is then added again, adjust molten The pH to 2-14 of liquid, is stirred to react in a water bath, and decompression filters, and obtained mixture B is washed to neutrality, then by mixture B drying is ground, and the mass ratio of the ammonium metavanadate and silicon carbide that contain in ammonium metavanadate solution is 500:1-10:1, the water-bath In the temperature that is stirred to react be 60-100 DEG C, time 1-5h；

Parameter setting during the ultrasonic disperse are as follows: 100-500W, working frequency 20-60KHz, time 1- 30min.；It is specially to filter under -0.1MPa pressure that the decompression, which filters,；The temperature of the drying is 60-120 DEG C, and the time is 1-5h。

Further, the SiC/C₃N₄/BiVO₄The preparation method of composite photo-catalyst, further comprising the steps of: D. will be walked Grinding obtained solid is heated to 200-500 DEG C from room temperature under 5-20 DEG C/min in rapid C, then calcines 1- at 200-500 DEG C 5h。

Further, the SiC/C₃N₄/BiVO₄The preparation method of composite photo-catalyst, comprising the following steps:

A. by silicon carbide ultrasonic disperse in the aqueous solution of melamine, 1-300min is stirred at 60-100 DEG C, then Cooling, decompression filters, and obtains solid mixture A, the quality of the melamine contained in the aqueous solution of silicon carbide and melamine Than are as follows: 1:25-1:200；

B. will solid mixture A drying after grind, be heated to 400-600 DEG C from room temperature under 5-20 DEG C/min, then in 1-5h is kept the temperature at 400-600 DEG C, cooling, grinding obtains SiC-C₃N₄；

C. by SiC-C₃N₄It is added in ammonium metavanadate solution, ultrasonic disperse, bismuth nitrate solution is then added again, adjust molten The pH to 2-14 of liquid, is stirred to react in a water bath, and decompression filters, and obtained mixture B is washed to neutrality, then by mixture B drying is ground, and the mass ratio of the ammonium metavanadate and silicon carbide that contain in ammonium metavanadate solution is 500:1-10:1, the water-bath In the temperature that is stirred to react be 60-100 DEG C, time 1-6h；

D. obtained solid will be ground in step C and be heated to 200-500 DEG C from room temperature under 5-20 DEG C/min, then in 200- 1-5h is calcined at 500 DEG C.

The beneficial effects of the present invention are:

SiC/C made from method of the invention₃N₄/BiVO₄The light degradation ability of composite photo-catalyst has obtained significantly mentioning Height, when the rhodamine B solution for being 10mg/L with 0.01g catalyst degradation 100mL concentration, the degradation rate of rhodamine B is in 30min When can reach 83-95%.

The present invention solves the problems, such as that semiconductor structure is unstable in the prior art.

Specific embodiment

Illustrated embodiment is to preferably be illustrated to the contents of the present invention, but is not that the contents of the present invention only limit In illustrated embodiment.So those skilled in the art carry out nonessential change to embodiment according to foregoing invention content Into and adjustment, still fall within protection scope of the present invention.

Embodiment 1

SiC/C₃N₄/BiVO₄The preparation method of composite photo-catalyst, the specific steps are as follows:

A. it weighs 1.2g melamine and is dissolved in 60mL100 DEG C of hot water (100 DEG C of water-bath heat preservations), be denoted as solution A, then will 0.02g silicon carbide is 300W in power, and into solution A, the time of ultrasonic disperse is ultrasound under the conditions of working frequency is 40KHz 2min stirs 10min under 90 DEG C of heated conditions；It then cools to room temperature, depressurizes and filter under -0.1MPa pressure, consolidate Body mixture A；

B. solid mixture A is put into baking oven, 1h is dried at 80 DEG C, is then ground, then from room under 5 DEG C/min Temperature is heated to 550 DEG C, then keeps the temperature 2h at 550 DEG C, is cooled to room temperature, and grinding obtains SiC-C₃N₄；

C. 0.1g SiC-C is weighed₃N₄It is added in the ammonium metavanadate solution that 10mL concentration is 0,05mol/L, is in power 300W, working frequency are ultrasonic disperse 2min under the conditions of 40KHz, and being then slowly added to 10mL concentration again is 0,05mol/L's Bismuth nitrate solution adjusts the pH to 4 of solution, is stirred to react 3h at 90 DEG C in water-bath, and decompression filters, the mixing that will be obtained Object B is washed to pH=7, and then mixture B is put into baking oven, and 1h is dried at 80 DEG C, then grind to get.

Embodiment 2

SiC/C₃N₄/BiVO₄The preparation method of composite photo-catalyst, the specific steps are as follows:

A. it weighs 1.2g melamine and is dissolved in 60mL100 DEG C of hot water (100 DEG C of water-bath heat preservations), be denoted as solution A, then will 0.02g silicon carbide is 300W in power, and into solution A, the time of ultrasonic disperse is ultrasound under the conditions of working frequency is 40KHz 2min stirs 10min under 90 DEG C of heated conditions；It then cools to room temperature, depressurizes and filter under -0.1MPa pressure, consolidate Body mixture A；

B. solid mixture A is put into baking oven, 1h is dried at 80 DEG C, is then ground, then from room under 5 DEG C/min Temperature is heated to 550 DEG C, then keeps the temperature 2h at 550 DEG C, is cooled to room temperature, and grinding obtains SiC-C₃N₄；

C. 0.1g SiC-C is weighed₃N₄It is added in the ammonium metavanadate solution that 10mL concentration is 0,05mol/L, is in power 300W, working frequency are ultrasonic disperse 2min under the conditions of 40KHz, and being then slowly added to 10mL concentration again is 0,05mol/L's Bismuth nitrate solution adjusts the pH to 4 of solution, is stirred to react 3h at 90 DEG C in water-bath, and decompression filters, the mixing that will be obtained Object B is washed to pH=7, and then mixture B is put into baking oven, and 1h is dried at 80 DEG C, is then ground；

D. obtained solid will be ground in step C to be placed in crucible with cover, be heated to 400 DEG C from room temperature under 5 DEG C/min, Then at 400 DEG C calcine 2h to get.

Embodiment 3

SiC/C₃N₄/BiVO₄The preparation method of composite photo-catalyst, the specific steps are as follows:

A. it weighs 1.2g melamine and is dissolved in 60mL100 DEG C of hot water (100 DEG C of water-bath heat preservations), be denoted as solution A, then will 0.02g silicon carbide is 300W in power, and into solution A, the time of ultrasonic disperse is ultrasound under the conditions of working frequency is 40KHz 2min stirs 10min under 90 DEG C of heated conditions；It then cools to room temperature, depressurizes and filter under -0.1MPa pressure, consolidate Body mixture A；

B. solid mixture A is put into baking oven, 1h is dried at 80 DEG C, is then ground, then from room under 5 DEG C/min Temperature is heated to 550 DEG C, then keeps the temperature 2h at 550 DEG C, is cooled to room temperature, and grinding obtains SiC-C₃N₄；

C. 0.1g SiC-C is weighed₃N₄It is added in the ammonium metavanadate solution that 10mL concentration is 0,05mol/L, is in power 300W, working frequency are ultrasonic disperse 2min under the conditions of 40KHz, and being then slowly added to 10mL concentration again is 0,05mol/L's Bismuth nitrate solution adjusts the pH to 10 of solution, is stirred to react 3h at 90 DEG C in water-bath, and decompression filters, mixed by what is obtained It closes object B to wash to pH=7, then mixture B is put into baking oven, 1h is dried at 80 DEG C, is then ground；

D. obtained solid will be ground in step C to be placed in crucible with cover, be heated to 400 DEG C from room temperature under 5 DEG C/min, Then at 400 DEG C calcine 2h to get.

Embodiment 4

SiC/C₃N₄/BiVO₄The preparation method of composite photo-catalyst, the specific steps are as follows:

A. it weighs 1.2g melamine and is dissolved in 60mL100 DEG C of hot water (100 DEG C of water-bath heat preservations), be denoted as solution A, then will 0.02g silicon carbide is 300W in power, and into solution A, the time of ultrasonic disperse is ultrasound under the conditions of working frequency is 40KHz 2min stirs 10min under 90 DEG C of heated conditions；It then cools to room temperature, depressurizes and filter under -0.1MPa pressure, consolidate Body mixture A；

B. solid mixture A is put into baking oven, 1h is dried at 80 DEG C, is then ground, then from room under 5 DEG C/min Temperature is heated to 550 DEG C, then keeps the temperature 2h at 550 DEG C, is cooled to room temperature, and grinding obtains SiC-C₃N₄；

C. 0.1g SiC-C is weighed₃N₄It is added in the ammonium metavanadate solution that 10mL concentration is 0,05mol/L, is in power 300W, working frequency are ultrasonic disperse 2min under the conditions of 40KHz, and being then slowly added to 10mL concentration again is 0,05mol/L's Bismuth nitrate solution adjusts the pH to 7 of solution, is stirred to react 3h at 90 DEG C in water-bath, and decompression filters, the mixing that will be obtained Object B is washed to pH=7, and then mixture B is put into baking oven, and 1h is dried at 80 DEG C, is then ground；

D. obtained solid will be ground in step C to be placed in crucible with cover, be heated to 400 DEG C from room temperature under 5 DEG C/min, Then at 400 DEG C calcine 2h to get.

Performance detection

To SiC/C made from embodiment 1-4₃N₄/BiVO₄Composite photo-catalyst and SiC/C₃N₄And BiVO₄Carry out photocatalysis Degradation effect experiment, the specific steps are as follows:

1, using colored dyes rhodamine B as target degradation product

(1) catalyst 10mg is weighed；

(2) in power be 300W, sieve that ultrasonic disperse is 10mg/L in 100mL concentration under the conditions of working frequency is 40KHz In red bright B simulated water sample, jitter time 2min；Using the 300W xenon lamp equipped with 420nm edge filter as simulated solar irradiation Source is measured the concentration of rhodamine B in water sample using the method for measuring solution absorbance, dropped according to formula under stirring conditions Solution rate=[1- (initial concentration-endpoint concentration)/initial concentration] × 100% calculates the degradation rate of photochemical catalyst, 30min degradation The results are shown in Table 1.

2, using colourless organic pollutant phenol as target degradation product

(1) catalyst 25mg is weighed；

(2) in power be 300W, the phenol that ultrasonic disperse is 10mg/L in 50mL concentration under the conditions of working frequency is 40KHz In simulated water sample, jitter time 2min；Using the 300W xenon lamp equipped with 420nm edge filter as simulated solar light source, Under conditions of stirring, the concentration of Phenol in Aqueous Solution is measured using liquid chromatography, according to formula degradation rate=[1- (initial concentration- Endpoint concentration)/initial concentration] × 100% degradation rate for calculating photochemical catalyst, 120min degradation results are as shown in table 1.

1 the performance test results of table

Sample	Embodiment 1	Embodiment 2	Embodiment 3	Embodiment 4	SiC/C3N4	BiVO4
							To the degradation rate of rhodamine B	85%	95%	83%	94%	75%	8%
The degradation rate of Pyrogentisinic Acid	50%	61%	52%	63%	20%	0%

As shown in Table 1, with SiC/C₃N₄And BiVO₄It compares, SiC/C made from embodiment 1-4₃N₄/BiVO₄Composite photocatalyst Agent is significantly improved to the degradation rate of phenol in rhodamine B in rhodamine B solution and phenol solution.Thus it proves, this hair SiC/C made from bright method₃N₄/BiVO₄The light degradation ability of composite photo-catalyst is significantly improved.Due to this this three First compound can effectively facilitate the transfer in light induced electron and hole, improve the utilization efficiency of photo-generated carrier, so three Synergistic effect is so that SiC/C₃N₄/BiVO₄The catalytic capability of composite photo-catalyst is significantly improved.

Repetitive test

Repeated experiment is carried out to rhodamine B photocatalytic degradation effect to composite photocatalyst material made from embodiment 1-4, Test method is same as above, and three times, test result is as shown in table 2 for photochemical catalyst retest made from each embodiment.

The repeated the performance test results of table 2 (to the degradation rate of rhodamine B)

As shown in Table 2, the photocatalysis effect of composite photo-catalyst retest three times made from embodiment 1-4 is without under obvious Drop.Thus it proves, SiC/C made from method of the invention₃N₄/BiVO₄The performance of composite photo-catalyst is stablized, and the present invention solves Semiconductor structure unstable problem in the prior art.

In addition, it should be understood that although this specification is described in terms of embodiments, but not each embodiment is only wrapped Containing an independent technical solution, this description of the specification is merely for the sake of clarity, and those skilled in the art should It considers the specification as a whole, the technical solutions in the various embodiments may also be suitably combined, forms those skilled in the art The other embodiments being understood that.

Claims (10)

1.SiC/C₃N₄/BiVO₄The preparation method of composite photo-catalyst, which comprises the following steps:

A. by silicon carbide ultrasonic disperse in the aqueous solution of melamine, 1-300min is stirred at 60-100 DEG C, is then cooled down, Decompression filters, and obtains solid mixture A；

B. it will be ground after solid mixture A drying, 400-600 DEG C be heated to from room temperature under 5-20 DEG C/min, then in 400- 1-5h is kept the temperature at 600 DEG C, cooling, grinding obtains SiC-C₃N₄；

C. by SiC-C₃N₄It is added in ammonium metavanadate solution, then ultrasonic disperse adds bismuth nitrate solution, adjust the pH of solution To 2-14, it is stirred to react in a water bath, decompression filters, and obtained mixture B is washed to neutrality, then dry mixture B, Grinding.

2. SiC/C according to claim 1₃N₄/BiVO₄The preparation method of composite photo-catalyst, which is characterized in that step A In, the mass ratio of the melamine contained in the aqueous solution of silicon carbide and melamine are as follows: 1:25-1:200.

3. SiC/C according to claim 1 or 2₃N₄/BiVO₄The preparation method of composite photo-catalyst, which is characterized in that

Parameter setting during the ultrasonic disperse are as follows: power 100-500W, working frequency 20-60KHz, time 1- 30min。

4. SiC/C according to claim 1,2 or 3₃N₄/BiVO₄The preparation method of composite photo-catalyst, which is characterized in that It is specially to filter under -0.1MPa pressure that the decompression, which filters,.

5. SiC/C according to claim 1,2,3 or 4₃N₄/BiVO₄The preparation method of composite photo-catalyst, feature exist In the temperature of the drying is 60-120 DEG C, time 1-5h.

6. according to claim 1, SiC/C described in 2,3,4 or 5₃N₄/BiVO₄The preparation method of composite photo-catalyst, feature It is, in step C, the mass ratio of the ammonium metavanadate and silicon carbide that contain in ammonium metavanadate solution is 500:1-10:1.

7. according to claim 1, SiC/C described in 2,3,4,5 or 6₃N₄/BiVO₄The preparation method of composite photo-catalyst, it is special Sign is that the temperature of the stirred in water bath reaction is 60-100 DEG C, time 1-6h.

8. according to claim 1, SiC/C described in 2,3,4,5 or 6₃N₄/BiVO₄The preparation method of composite photo-catalyst, it is special Sign is, comprising the following steps:

A. by silicon carbide ultrasonic disperse in the aqueous solution of melamine, 1-300min is stirred at 60-100 DEG C, is then cooled down, Decompression filters, and obtains solid mixture A, the mass ratio of the melamine contained in the aqueous solution of silicon carbide and melamine are as follows: 1:25-1:200；

B. it will be ground after solid mixture A drying, 400-600 DEG C be heated to from room temperature under 5-20 DEG C/min, then in 400- 1-5h is kept the temperature at 600 DEG C, cooling, grinding obtains SiC-C₃N₄；

C. by SiC-C₃N₄It is added in ammonium metavanadate solution, then bismuth nitrate solution is added in ultrasonic disperse again, adjust solution PH to 2-14, is stirred to react in a water bath, and decompression filters, and obtained mixture B is washed to neutrality, is then dried mixture B It does, grinding, the mass ratio of the ammonium metavanadate and silicon carbide that contain in ammonium metavanadate solution is 500:1-10:1, is stirred in the water-bath The temperature for mixing reaction is 60-100 DEG C, time 1-6h；

Parameter setting during the ultrasonic disperse are as follows: 100-500W, working frequency 20-60KHz, time 1-30min. It is specially to filter under -0.1MPa pressure that the decompression, which filters,；The temperature of the drying is 60-120 DEG C, time 1-5h.

9. according to claim 1, SiC/C described in 2,3,4,5,6,7 or 8₃N₄/BiVO₄The preparation method of composite photo-catalyst, It is characterized in that, further comprising the steps of: D. will grind obtained solid and be heated under 5-20 DEG C/min from room temperature in step C 200-500 DEG C, 1-5h then is calcined at 200-500 DEG C.

10. SiC/C according to claim 9₃N₄/BiVO₄The preparation method of composite photo-catalyst, which is characterized in that including Following steps:

A. by silicon carbide ultrasonic disperse in the aqueous solution of melamine, 1-300min is stirred at 60-100 DEG C, is then cooled down, Decompression filters, and obtains solid mixture A, the mass ratio of the melamine contained in the aqueous solution of silicon carbide and melamine are as follows: 1:25-1:200；

B. it will be ground after solid mixture A drying, 400-600 DEG C be heated to from room temperature under 5-20 DEG C/min, then in 400- 1-5h is kept the temperature at 600 DEG C, cooling, grinding obtains SiC-C₃N₄；

C. by SiC-C₃N₄It is added in ammonium metavanadate solution, then bismuth nitrate solution is added in ultrasonic disperse again, adjust solution PH to 2-14, is stirred to react in a water bath, and decompression filters, and obtained mixture B is washed to neutrality, is then dried mixture B It does, grinding, the mass ratio of the ammonium metavanadate and silicon carbide that contain in ammonium metavanadate solution is 500:1-10:1, is stirred in the water-bath The temperature for mixing reaction is 60-100 DEG C, time 1-6h；

D. obtained solid will be ground in step C and be heated to 200-500 DEG C from room temperature under 5-20 DEG C/min, then in 200-500 1-5h is calcined at DEG C.